Hydraulic rotary barrel pumps or motors

ABSTRACT

A barrel pump or motor has a rotatable shaft which is coupled to a barrel for common rotation, the shaft being rotatably supported at one end thereof from fixed structure and coupled to the barrel at the other end so as to be freely rotatable and unsupported between the ends. Transverse forces produced by reciprocating pistons in the barrel are transmitted to an inclined plate, to which the pistons are connected, and thence to a fixed support interposed between the shaft and the barrel to prevent application of transverse load on the shaft so that the shaft will run true. The barrel is mounted on the support via a bearing which permits the barrel to make slight angular movement with respect to the support and the shaft and the coupling between the barrel and shaft accommodates such angular movement so that the end face of the barrel can remain in sealed relation with a slide-face on which it rotates.

United States Patent [191 Lucien Jan. 21, 1975 [75] Inventor: Rene Lucien, Neuilly sur Seine,

Hauts de Seine, France [73] Assignee: Societe Anonyme dite: Messier, Paris, France 22 Filed: July 20,1973

[21] Appl. No.: 380,949

Related US. Application Data [63] Continuation of Ser. No. 18,593, March 3, 1970, abandoned, which is a continuation-in-part of Ser. No. 598,410, Dec. 1, 1966, Pat. No. 3,545,338.

Primary ExaminerWilliam L, Freeh Attorney, Agent, or Firm-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT A barrel pump or motor has a rotatable shaft which is coupled to a barrel for common rotation, the shaft being rotatably supported at one end thereof from fixed structure and coupled to the barrel at the other end so as to be freely rotatable and unsupported between the ends. Transverse forces produced by reciprocating pistons in the barrel are transmitted to an in clined plate, to which the pistons are connected, and thence to a fixed support interposed between the shaft and the barrel to prevent application of transverse load on the shaft so that the shaft will run true. The barrel is mounted on the support via a hearing which permits the barrel to make slight angular movement with respect to the support and the shaft and the coupling between the barrel and shaft accommodates such angular movement so that the end face of the barrel can remain in sealed relation with a slide-face on which it rotates.

5 Claims, 4 Drawing Figures PATENTEU JANZ] I975 SHEET 1 BF 2 PATENTEDJRNZ 1 5 a. as 1.276 SHEET 2 OF 2 HIM HYDRAULIC ROTARY BARREL PUMPS OR MOTORS CROSS-RELATED APPLICATION This application is a continuation of application Ser. No. 18,593 (now abandoned) filed Mar. 3, 1970 which in turn was a continuation-in-part of my earlier application Ser. No. 598,410 filed Dec. 1, 1966 (now issued as U.S. Pat. No. 3,545,338) and claiming priority of my application filed in France on Dec. 3, 1965.

BRIEF SUMMARY OF THE INVENTION The present invention relates to hydraulic rotary barrel pumps or motors with a distribution valve-gear of the so-called slide-face type. In the description which follows below, reference will be made solely to pumps of this type, but it is understood that the arrangements described are equally applicable to hydraulic motors and that this application falls within the scope of the invention.

In pumps of this kind, the suction of the fluid into the cylinders of the barrel and its delivery under pressure from the said cylinders is effected through two ports in a plate or slide-face perpendicular to the axis of the barrel, against which is applied a corresponding plane surface of the said barrel. The cylinders open into this plane surface and communicate successively with one or the other of the said ports in the slide-face during the course of rotation of the barrel.

It is well known that these pumps must comply simultaneously with two essential conditions:

1. The shearing forces due to the pressure to which the barrel is subjected must be resisted in the most advantageous manner, and the most logical solution consists of resisting the resultant of these forces at the point of its application on the axis of the barrel.

2. The barrel must be floatably mounted, that is to say it must be able to make small angular displacements with respect to the axis of the pump, in order to be constantly and perfectly applied against the slide-face.

In order to satisfy these conditions, it is known to mount the barrel in a bearing arranged at the exterior of the barrel at the resultant of the shearing forces, the desired freedom of displacement being provided by the inherent play of the bearing.

However, this solution requires the use of a bearing with a large diameter, which involves many disadvantages. In particular, the power absorbed by the bearing is considerable, which reduces the efficiency in the case of high speeds of rotation, and the piston controlling the inclination of the plate, which regulates the output of the pump in known manner, must be mounted far from the axis of the pump, which results in an increase in the external diameter in the case of self-regulating pumps.

The present invention has for its object to provide a hydraulic barrel pump in which the barrel is floatably mounted and does not present the disadvantages outlined above, and wherein a bearing of small diameter is arranged in the interior of the pump barrel so as to resist the shearing forces due to the pressure, at the point of application of their resultant, and prevent application onto the drive shaft of the barrel while also providing the barrel with the small amount of freedom of movement which is necessary.

As the bearing is of small size, the power absorbed by it is very small, and it is mounted inside the barrel, the

pump may have a small external diameter, even in the case of a self-regulating pump, since the piston operating the regulating plate may in this case be arranged close to the axis of the pump and the plate may also have a simpler form.

In order to permit slight angular displacements, it is only necessary to give the bearing a slightly domed internal seating and to provide a driving system which will permit such movements, for example to use a spline connection comprising a relatively long portion fixed to one of the extremities of the driving shaft and coupled by a radial web to a short portion which directly drives the barrel.

The drive shaft is supported in a bearing at one end thereof and extends cantilever fashion therefrom into the barrel for engagement therewith as the spline connection, the shaft being otherwise free and unsupported between the bearing and spline connection so as to run straight and true. A support is interposed between the barrel and shaft to resist the shearing forces and prevent application thereof to the shaft.

BRIEF DESCRIPTION OF THE DRAWING:

FIG. 1 is a diagrammatic view in partial axial section of a pump comprising the arrangements in accordance with the invention;

FIG. 2 is a detail section on a larger scale, illustrating the driving system of the barrel of this pump and the floating mounting of this barrel;

FIG. 3 is an axial cross-section of a constant-output pump in accordance with the invention; and

FIG. 4 is an axial half-section of an alternative form of the pump according to the invention.

DETAILED DESCRIPTION Referring first to FIGS. 1 and 2:

Barrel pumps of a known type comprise a cylindrical frame 1 closed at its extremity by a bottom 2, in which are formed an annular array of fluid admission and delivery orifices 0. A barrel 3 driven by a shaft 4 rotates in the interior of the frame 1, remaining closely applied at one of its extremities against the flat internal face F (slide face) of the bottom 2 in order to put alternately in communication, during the course of its rotation, cylinders C formed in the barrel, which open out into the said extremity and inside which pistons 5 are adapted to move. The reciprocating motion of the pistons is effected in known manner by a plate 6 inclined with respect to the axis of the barrel, against which shoes 7, coupled to the universal head joints 8 of the pistons are in rubbing contact.

The force E, due to the pressure withstood by the pistons, can be resolved into a force F perpendicular to the plate 6 and a shearing force T perpendicular to the axis of the pump. The resultant of these shearing forces, 2 T is also perpendicular to the axis, its point of application being the point of intersection of this axis with the plane defined by the centers of the universal joints 8.

In accordance with the invention, a bearing of small diameter is provided inside the barrel 3, between the barrel and a support 9, coaxial with the shaft 4 which passes through it, in order to resist the resultant of the shearing forces at the point of its application.

This bearing can be constituted by a roller bearing 10 (FIG. 2), for example a needle bearing, or it may be in the form of a journal bearing, this latter solution having certain advantages for some types of pumps, especially for pumps of small output and of very small size. The bearing may also be in the form of a fluid bearing, or it may be a bearing of any other type.

The internal seating 9a of the bearing is slightly domed so as to permit the barrel to make slight angular movements with respect to its axis, in order that it may remain constantly applied in a perfect manner against the slide-face F of the pump.

The freedom of movement of the barrel is further ensured by a driving system which forms part of the invention and which is illustrated in FIG. 2. The driving system comprises a connection including a driving sleeve 11, of which one long portion 11a is directly actuated by the shaft 4 with which it cooperates, for example, through the intermediary of a system of splines, and of which one shorter portion 11b, coupled to portion 11a by a radial web 1 1c, directly drives the barrel 3, for example, by means of a system of splines.

This method of driving, emplpyed in combination with the bearing for resisting the shearing forces defined above, has numerous advantages. In fact, by reason of the short length of the portion 11b, the barrel can readily move to a distance c, away from the axis of the pump (FIG. 2), the bearing 10 being angularly displaced over the domed surface 9a. If a represents the distance between the sleeve and the bearing 10, while b is the distance between this bearing and the bearing 12 on which the support 9 is mounted, it is clear that the barrel can readily move angularly with respect to the axis of the pump through an angle defined by tan 0 C/a+b.

The lengths of the splines of the portions 11a and 11b of the sleeve 11 are naturally a function of the diameters of the shaft 4, the portion 1 1a, and the portion 11b.

The driving system described above may, however, be replaced by any other desired method of driving which permits a slight angular displacement of the barrel, such as, for example, a cardan joint or the like.

As already stated, the fact of utilizing a bearing mounted inside the barrel, makes it possible to employ a bearing having dimensions considerably smaller than those of an external bearing, since the tangential speeds are lower. On the other hand, the small dimensions of the internal bearing obviously ensure a better efficiency of the pump.

In accordance with the invention, it is to be noted that support 9 is interposed between barrel 3 and shaft 4 and intercepts the shear load to prevent application thereof to the shaft. Thus, shaft 4 which is essentially freely cantilevered in the barrel 3 beyond bearing 12 and extends with clearance in support 9, is not externally loaded and hence runs straight and true avoiding imbalance, vibration, leakage and wear of the bearings. In the known pumps, the shaft resists the shear force and hence undergoes bending deflection which produces the undesirable characteristics noted above as a consequence of the deviation of the shaft from absolute straightness. Essentially, therefore, the shaft 4, which is rotatably supported in bearing 12 at one end and in the connection at the other end, is freely rotatable and unsupported therebetween and not subjected to load The invention having been described in respect of its principle, it will now be described by way of example and without limitation, in its application to a constant output pump illustrated in FIG. 3, and to FIG. 4 showing an alternative form applicable to any type of pump in accordance with the invention.

The constant-output pump illustrated in FIG. 3 differs very little from that which is shown in FIG. 1. The parts already referred to have been given the same reference numbers and will not be described in detail.

In FIG. 3 the cylinders 14 provided in the barrel 3 have been shown in entirety. The barrel is applied in known manner against the slide-face F by a spring 16 which is interposed between a ring 17 fixed on the shaft 4 and the web lie of the sleeve 11. The operation of a pump of this type is well known and will not therefore be described.

It will be noted that the pump shown in FIG. 3 comprises a barrel made of one piece and therefore of one material only.

The different parts of the barrel are not, however, subjected to the same stresses and there is no material which can be utilized indifferently for all these parts. It is, in fact, preferable that the extremity of the barrel applied against the slideface F should be of a material having a low hardness, whereas the seating of the bearing 10 and also, where applicable, the part subjected to the driving torque of the sleeve 11, must be as hard as possible.

The arrangements of the bearing 10 and the sleeve 11 particular to the invention make it possible to utilize composite barrel 3 consisting of only two parts of material of different kinds, depending on the purposes desired. Thus, for example, FIG. 4 shows an alternative form of the pump, in which the barrel 3 is composed of two parts, one 3a being supported against the slide-face 2 and of a relatively soft material, while the other 3b cooperates with the sleeve 11 and the bearing 10 and is of a relatively hard material.

It should be noted that a barrel of this kind is simple since, with a bearing mounted externally of the barrel for resisting the shearing forces, it would be very difficult if not impossible to utilize a composite barrel comprising only two parts of different kinds. In the case of use of a journal bearing, a layer of anti-friction material can, of course, be applied on the internal face of the portion 3b.

In the pumps which have been described above, the pistons are parallel to the axis of the barrel. They could, of course, be equally well inclined to that axis.

In the say way, the hollow support 9 which serves as an internal seating for the bearing which resists the shearing forces could equally well be a solid support, the outlet of the driving shaft being then effected through the bottom of the pump.

The bearing which resists the shearing forces may equally well be supported on a ring fitted over the support.

The support may also be anchored to the bottom, the outlet of the driving shaft then being effected either through the bottom or through the opposite extremity.

In all cases, however, the shear load is intercepted by the support and prevented from being applied to the shaft.

As has already been indicated, all the characteristics of the pumps which have just been described could also be applied to rotating barrel hydraulic motors, without thereby departing from the scope of the invention.

What is claimed is:

l. A hydraulic pump or motor of the rotating and floating, barrel type, comprising a cylindrical fixed casing provided with a bottom having a slide-face with first and second orifices therein; a barrel supported in said casing for rotation about an axis; said barrel having cylinders and slidable pistons in said cylinders; means for placing said cylinders into communication alternately with said first and second orifices in said slide-face; means including an inclined plate for reciprocally moving said pistons in said cylinders and producing forces on said pistons having components acting as shear forces applied to said barrel; a rotatable shaft having opposite ends; connecting means between said barrel and one of said ends of the shaft for transmitting rotational drive therebetween; a support interposed between between said barrel and said shaft and in coaxially spaced relation with said shaft to provide a clearance therewith; means rigidly securing said support to said casing; a first bearing between said support and the other end of said shaft rotatably supporting said shaft in the support, said shaft extending in cantilever fashion from said first bearing; and a second bearing within the barrel between said support and said barrel, said second bearing being of small diameter and disposed at the point of application on the axis of said barrel of the resultant of the shear forces applied to said pistons to resist said shear forces and transmit the same to said support and prevent application of load to said shaft,

said second bearing being constructed to permit said barrel to make slight angular movements with respect to said support and thereby with respect to said axis of rotation of the shaft, said first bearing being axially displaced with respect to the second bearing on the side remote relative to the slide face, said shaft being freely rotatable and unsupported from the first bearing to the connection means, said connecting means being constructed to provide radial play of the shaft to accommodate said angular movements of the barrel.

2. A hydraulic pump or motor as claimed in claim 1, wherein said means connecting said barrel to the shaft for rotation therewith comprises a spline connection 3. A hydraulic pump or motor as claimed in claim 1, wherein said barrel is in sealed relation with said slideface, said connecting means comprising a connection permitting transverse movement of the barrel with respect to the shaft without application of transverse load to the shaft and while the barrel remains in sealed relation with said slide-face.

' 4. A hydraulic pump or motor as claimed in claim 1, wherein said support has a seating for said bearing which comprises a slightly domed portion.

5. A hydraulic pump and motor as claimed in claim 1, wherein said barrel comprises a first portion in contact with said slide-face and a second portion secured to the first portion and engaging said second bearing and said connecting means, said second portion being constituted of harder material than said first. 

1. A hydraulic pump or motor of the rotating and floating barrel type, comprising a cylindrical fixed casing provided with a bottom having a slide-face with first and second orifices therein; a barrel supported in said casing for rotation about an axis; said barrel having cylinders and slidable pistons in said cylinders; means for placing said cylinders into communication alternately with said first and second orifices in said slideface; means including an inclined plate for reciprocally moving said pistons in said cylinders and producing forces on said pistons having components acting as shear forces applied to said barrel; a rotatable shaft having opposite ends; connecting means between said barrel and one of said ends of the shaft for transmitting rotatiOnal drive therebetween; a support interposed between between said barrel and said shaft and in coaxially spaced relation with said shaft to provide a clearance therewith; means rigidly securing said support to said casing; a first bearing between said support and the other end of said shaft rotatably supporting said shaft in the support, said shaft extending in cantilever fashion from said first bearing; and a second bearing within the barrel between said support and said barrel, said second bearing being of small diameter and disposed at the point of application on the axis of said barrel of the resultant of the shear forces applied to said pistons to resist said shear forces and transmit the same to said support and prevent application of load to said shaft, said second bearing being constructed to permit said barrel to make slight angular movements with respect to said support and thereby with respect to said axis of rotation of the shaft, said first bearing being axially displaced with respect to the second bearing on the side remote relative to the slide face, said shaft being freely rotatable and unsupported from the first bearing to the connection means, said connecting means being constructed to provide radial play of the shaft to accommodate said angular movements of the barrel.
 2. A hydraulic pump or motor as claimed in claim 1, wherein said means connecting said barrel to the shaft for rotation therewith comprises a spline connection
 3. A hydraulic pump or motor as claimed in claim 1, wherein said barrel is in sealed relation with said slide-face, said connecting means comprising a connection permitting transverse movement of the barrel with respect to the shaft without application of transverse load to the shaft and while the barrel remains in sealed relation with said slide-face.
 4. A hydraulic pump or motor as claimed in claim 1, wherein said support has a seating for said bearing which comprises a slightly domed portion.
 5. A hydraulic pump and motor as claimed in claim 1, wherein said barrel comprises a first portion in contact with said slide-face and a second portion secured to the first portion and engaging said second bearing and said connecting means, said second portion being constituted of harder material than said first. 